books.google.com - Complex behavior can occur in any system made up of large numbers of interacting constituents, be they atoms in a solid, cells in a living organism, or consumers in a national economy. Analysis of this behavior often involves making important assumptions and approximations, the exact nature of which...http://books.google.com/books/about/Foundations_of_Complex_system_Theories.html?id=YCaTftszYFsC&q=electrons&utm_source=gb-gplus-shareFoundations of Complex-system Theories